Stratification of phaco-trabectome surgery results using a\ud glaucoma severity index

Purpose: Nonsurgical glaucoma therapy reduces intraocular pressure (IOP) by a percentage that is similar for most patients. Recently introduced microincisional glaucoma surgeries are different because they remove the trabecular meshwork that constitutes the primary resistance to outflow. We hypothesized that because of this, the resulting postoperative IOP, rather than the relative reduction, had to be independent of glaucoma severity. We applied a glaucoma index (GI) to analyze outcomes of trabectome surgery combined with phacoemulsification (PT) by glaucoma severity.\ud Methods: Only PT with 12 month follow up and no other surgeries were included. GI incorporated preoperative IOP, medications (meds) and visual field (VF). Baseline IOP was divided into 4 groups, <20 mmHg, 20-29 mmHg, 30-39 mmHg, and above 40 and assigned with 1 to 4 points. Meds was divided into 4 groups: ≤1, 2, 3, or ≥4, and assigned values of 1 to 4. VF was separated into 4 groups with points from 1 to 4: mild, moderate, advanced and end stage. GI was then defined as VF*meds*IOP and separated into GI1: